glDrawBuffer Subroutine

OpenGL 1.1 for AIX: Reference Manual

glDrawBuffer Subroutine

Purpose

Specifies which color buffers are to be used for drawing.

Library

OpenGL C bindings library: libGL.a

C Syntax

void glDrawBuffer(GLenum Mode)

Parameters

Mode

Specifies up to four color buffers to be drawn into. Symbolic constants GL_NONE, GL_FRONT_LEFT, GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT, GL_BACK, GL_LEFT, GL_RIGHT, GL_FRONT_AND_BACK, and GL_AUXi, where i is between 0 and GL_AUX_BUFFERS - 1, are accepted. (GL_AUX_BUFFERS is not the upper limit; use glGet to query the number of available aux buffers.) The default value is GL_FRONT for single buffered contexts, and GL_BACK for double buffered contexts.

Description

When colors are written to the frame buffer, they are written into the color buffers specified by the glDrawBuffer subroutine. The specifications are:

GL_NONE	No color buffers are written.
GL_FRONT_LEFT	Only the front left color buffer is written.
GL_FRONT_RIGHT	Only the front right color buffer is written.
GL_BACK_LEFT	Only the back left color buffer is written.
GL_BACK_RIGHT	Only the back right color buffer is written.
GL_FRONT	Only the front left and front right color buffers are written. If there is no front right color buffer, only the front left color buffer is written.
GL_BACK	Only the back left and back right color buffers are written. If there is no back right color buffer, only the back left color buffer is written.
GL_LEFT	Only the front left and back left color buffers are written. If there is no back left color buffer, only the front left color buffer is written.
GL_RIGHT	Only the front right and back right color buffers are written. If there is no back right color buffer, only the front right color buffer is written.
GL_FRONT_AND_BACK	All the front and the back color buffers (front left, front right, back left, back right) are written. If there are no back color buffers, only the front left and front right color buffers are written. If there are no right color buffers, only the front left and back left color buffers are written. If there are no right or back color buffers, only the front left color buffer is written.
GL_AUXi	Only auxiliary color buffer i is written.

If more than one color buffer is selected for drawing, blending or logical operations are computed and applied independently for each color buffer and may produce different results in each buffer.

Monoscopic contexts include only left buffers, while stereoscopic contexts include both left and right buffers. Likewise, single-buffered contexts include only front buffers, while double-buffered contexts include both front and back buffers. The context is selected at GL initialization.

Notes

It is always the case that GL_AUXi = GL_AUX0 + i.

Errors

GL_INVALID_ENUM	Mode is not an accepted value.
GL_INVALID_OPERATION	None of the buffers indicated by Mode exists.
GL_INVALID_OPERATION	The glDrawBuffer subroutine is called between a call to glBegin and the corresponding call to glEnd.

Associated Gets

Associated gets for the glDrawBuffer subroutine are as follows. (See the glGet subroutine for more information.)

glGet with argument GL_DRAW_BUFFER

glGet with argument GL_AUX_BUFFERS.

Files

/usr/include/GL/gl.h

Contains C language constants, variable type definitions, and ANSI function prototypes for OpenGL.

Related Information

The glBegin or glEnd subroutine, glBlendFunc subroutine, glColorMask subroutine, glIndexMask subroutine, glLogicOp subroutine, glReadBuffer subroutine.

OpenGL Overview.